A number of laboratory studies have addressed the question of how people integrate different pieces of information to form an overall evaluative judgment. Models of information integration, i.e., the adding model and the averaging model, were tested by gathering questionnaire data from 233 respondents in 17 groups who were expected to vary in their attitudes from strongly pro-nuclear to strongly anti-nuclear. The adding model predicted that a larger number of evaluatively consistent cognitions would be associated with more extreme attitudes. The averaging model predicted that one positive cognition would produce a more extreme attitude than the combination of one negative and two positive cognitions. Data analyses confirmed the prediction of the adding model. Among subjects who held all evaluatively consistent cognitions, a larger number of cognitions were associated with significantly more extreme attitudes. No support was found for the averaging model, suggesting it does not generalize well to a nonlaboratory situation in which subjects are asked to provide traits that they associate with a familiar stimulus. Further research is needed to identify the conditions under which diffeent integration models apply. (JAC)